Abstract: A corona-discharge type gas flow meter includes a discharge electrode, and a split collecting electrode, the collecting electrodes are connected to input amplifiers which act as current-to-voltage converters receiving a reference signal from an integrator acting to integrate the sum of the outputs of the input amplifiers. The output of the integrator is used to control an EHT supply for the discharge. An output amplifier provides a flow signal by running the signal from one input amplifier, from a variable offset nulling signal derived via an amplifier from the integrator and a fixed offset nulling signal from a potentiometer.

Abstract: A linear displacement transducer includes a first elongated magnetizable member having first and second pole pieces which extend parallel with each other over the full length of said first member and which are of substantially constant width along their length. A first winding is wound around part but not all of said first member, a second winding is wound around the full length of the first member. A second elongated member having at least a part which is shorter than said first elongate member is movable linearly relative to the first member in a direction parallel with the longitudinal axis of the first member, such that a substantially constant gap is maintained between the members, to vary the magnetic coupling between the first and second windings when an a.c. signal is applied, in use, to one of the windings.

Abstract: Apparatus for measuring the mass flow of a fluid comprises a hollow collector electrode assembly through which the fluid flows. The collector electrode assembly includes a central electrode disposed between and insulated from first and second outer electrodes. An ionizing electrode comprising a length of conductive wire is supported coaxially within the central collector electrode. A voltage source is provided for applying between the ionizing electrode and the collector electrode assembly a potential difference sufficient to ionize the fluid. The ions thereby produced at the ionizing electrode migrate towards the central collector electrode but are displaced in the direction of fluid flow by an amount dependent upon the mass flow of the fluid. A differential amplifier is responsive to the number of ions migrating to the outer collector electrodes to provide a measure of the displacement of the ions by the fluid flowing through the collector electrode assembly.